title: CMY-42, a novel plasmid-mediated CMY-2 variant AmpC beta-lactamase.
abstract: We isolated a clinical Escherichia coli strain with an antimicrobial resistance phenotype characteristic for the expression of an AmpC beta-lactamase. Molecular methods revealed a novel, plasmid-localized variant of CMY-2 with a substitution of valine 231 for serine (V231S), which was designated CMY-42. Like the CMY-2-like AmpC beta-lactamase CMY-30, carrying the substitution V231G, CMY-42 displayed increased activity toward expanded spectrum cephalosporins. This finding supports the hypothesis that a bulky side chain at position 231 (Ambler's position 211) may pose a steric clash with certain cephalosporins hindering the access of the AmpC beta-lactamase; however, additional phenomena may account for the observed hydrolytic properties.
authors.affiliation: Institute of Medical Microbiology, Virology and Hygiene, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany. m.hentschke@uke.de
authors.forename: Moritz
authors.initials: M
authors.lastname: Hentschke
authors.forename: Stathis D
authors.initials: SD
authors.lastname: Kotsakis
authors.forename: Manuel
authors.initials: M
authors.lastname: Wolters
authors.forename: Peter
authors.initials: P
authors.lastname: Heisig
authors.forename: Vivi
authors.initials: V
authors.lastname: Miriagou
authors.forename: Martin
authors.initials: M
authors.lastname: Aepfelbacher
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002511:Cephalosporins / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial / Q000187:drug effects / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000188:drug therapy / Q000235:genetics / Q000382:microbiology*; D029968:Escherichia coli Proteins / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D010957:Plasmids / Q000235:genetics* / Q000378:metabolism; D012694:Serine / Q000235:genetics / Q000378:metabolism; D013530:Surgical Wound Infection / Q000188:drug therapy / Q000235:genetics / Q000382:microbiology*; D014633:Valine / Q000235:genetics / Q000378:metabolism; D001618:beta-Lactamases / Q000235:genetics* / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D029968:Escherichia coli Proteins; D012694:Serine; C103022:beta-lactamase CMY-2; D001618:beta-Lactamases; C561294:beta-lactamase CMY-42, E coli; D014633:Valine